Skeletal muscles with antagonistic muscular actions: morphological, contractile and metabolic characteristics

The muscles can perform the same function in a specific segment (muscles of fast and slow contraction), and at the same time be antagonistic in relation to muscular action (flexors or extensors). The present research aimed to study the morphology, frequency and metabolism of fiber types and the contractile characteristics of extensor and flexors muscles of rabbit. We studied muscles anterior tibialis (AT), flexor digitorum supeficialis (FDS), extensor digitorum longus (EDL) and posterior tibialis (PT). The muscles were submitted to the techniques HE, NADH-TR and myofibrillar ATPase. In EDL and PT extensor muscles, the frequencies of red (SO + FOG) and white fibers (FG) were 68.77% and 31.23% versus 58.87% and 41.13%, respectively. In the AT and FDS flexor muscles, these frequencies were 75.14% and 24.86% versus 73.89% and 26.11%, respectively. In extensor muscles, the percentage of slow contraction fibers was 8.05% in EDL and 9.74% in PT, and in fast contraction, 91.95% in EDL and 90.26% in PT. In flexors, the slow contraction frequencies were 12.35% in AT and 8.17% in FDS, and in fast contraction, 87.65% and 91.83%, respectively. Skeletal muscles with antagonistic muscular actions (flexors and extensors) the morphological, contractile and metabolic characteristics are identical.

Electromyographic activity of shoulder muscles during exercises performed with oscillatory and non-oscillatory poles

CONTEXTUALIZAÇÃO: A dor e a disfunção no complexo articular do ombro é comumente encontrada na prática fisioterapêutica. Essas anormalidades musculoesqueléticas estão relacionadas à instabilidade e inadequado funcionamento cinemático, que dependem da integridade dos tecidos musculares. Assim, no sentido de prevenir e reabilitar esses sintomas, o uso da haste oscilatória vem sendo implantado para melhorar os resultados de técnicas cinesioterapêuticas. OBJETIVOS: Analisar a atividade eletromiográfica (EMG) dos músculos que estabilizam a articulação do ombro durante a realização de exercícios com haste oscilatória e haste não-oscilatória. MÉTODOS: Participaram do estudo 12 voluntárias com idade de 20,4±1,9 anos. Os dados EMG foram coletados nos músculos trapézio superior (TrS), trapézio inferior (TrI) e deltoide médio (DM) durante três diferentes exercícios realizados com haste oscilatória e haste não-oscilatória. O sinal EMG foi analisado no domínio do tempo pelo cálculo do Root Mean Square (RMS). Os valores de RMS foram normalizados pelo valor de pico obtido em todas as tentativas por cada músculo. A análise estatística foi feita com os testes ANOVA para medidas repetidas e post-hoc de Bonferroni. RESULTADOS: A atividade EMG dos músculos TrS, TrI e DM foi significativamente maior nos exercícios com haste oscilatória do que com haste não-oscilatória (todos p<0,001). Não foram significativas as diferenças na ativação desses músculos entre os exercícios. CONCLUSÃO: Os resultados do presente estudo indicaram que a haste oscilatória requisitou maior atividade EMG dos músculos do ombro e, assim, pode ser um instrumento útil no treinamento desses músculos.

Electromyographic activity of trunk muscles during exercises with flexible and non-flexible poles

Objective: Hand-held flexible poles which are brought into oscillation to cause alternating forces on trunk, are advocated as training devices that are supposed to solicit increased levels of stabilizing trunk muscle activity. The aim of this study was to verify this claim by comparing electromyographic (EMG) activity of trunk muscles during exercises performed with a flexible pole and a rigid pole.Methods: Twelve healthy females performed three different exercises with flexible and rigid poles. EMG activity of iliocostalis lumborum (IL), multifidus (MU), rectus abdominis (RA), external oblique (EO) and internal oblique (IO), and was continuously measured. The EMG signals were analyzed in time domain by calculation of the Root Mean Square (RMS) amplitudes over 250 ms windows. The mean RMS-values over time were normalized by the maximum RMS obtained for each muscle.Results: The IO showed a 72% greater EMG activity during the exercises performed with the flexible pole than with the rigid pole (p = 0.035). In exercises performed in standing, the IO was significantly more active than when sitting (p = 0.006).Conclusion: As intended, the cyclic forces induced by the oscillating pole did increase trunk muscle activation. However, the effect was limited and significant for the IO muscle only.

Effects of phonophoresis with Arnica montana onto acute inflammatory process in rat skeletal muscles: An experimental study

This study aimed at verifying the effects of phonophoresis associated with Arnica montana on the acute phase of an inflammatory muscle lesion. Forty Wistar male rats (300 +/- 50 g), of which the Tibialis Anterior muscle was surgically lesioned, were divided into four groups (n = 10 each): control group received no treatment; the ultrasound group (US) was treated in pulsed mode with 1-MHz frequency, 0.5 W/cm(2) intensity (spatial and temporal average - SATA), duty cycle of 1: 2 (2 ms on, 4 ms off, 50%), time of application 3 min per session, one session per day, for 3 days; the phonophoresis or ultrasound plus arnica (US+A) group was treated with arnica with the same US parameters plus arnica gel; and the arnica group (A) was submitted to massage with arnica gel, also for 3 min, once a day, for 3 days. Treatment started 24 h after the surgical lesion. on the 4th day after lesion creation, animals were sacrificed and sections of the lesioned, inflamed muscle were removed for quantitative (mononuclear and polymorphonuclear cell count) and qualitative histological analysis. Collected data from the 4 groups were statistically analyzed and the significance level set at p < 0.05. Results show higher mononuclear cell density in all three treated groups with no significant difference between them, but values were significantly different (p < 0.0001) when compared to control group's. As to polymorphonuclear cell density, significant differences were found between control group (p = 0.0134) and US, US+A and A groups; the arnica group presented lesser density of polymorphonuclear cells when compared (p = 0.0134) to the other groups. No significant difference was found between US and US+A groups. While the massage with arnica gel proved to be an effective anti-inflammatory on acute muscle lesion in topic use, these results point to ineffectiveness of Arnica montana phonophoresis, US having seemingly checked or minimized its anti-inflammatory effect. (C) 2008 Elsevier B. V. All rights reserved.

Lumbar muscles recruitment during resistance exercise for upper limbs

The aim of this study was to evaluate the EMG activity of lumbar multifidus (MU), longissimus thoracis (LT) and iliocostalis (IC) muscles during an upper limb resistance exercise (biceps curl). Ten healthy males performed maximal voluntary isometric contraction (MVC) of the trunk extensors, after this, the biceps curl exercise was executed at 25%, 30%, 35% and 40% one repetition maximum during 1 min, with 10 min rest between them. EMG root mean square (RMS) and median frequency (MFreq) were calculated for each lifting and lowering of the bar during the exercise bouts, to calculate slopes and intercepts. The results showed increases in the RMS and decreases in the MFreq slopes. RMS slopes were no different between muscles, indicating similar fatigue process along the exercise irrespective of the load level. MU and LT presented higher RMS irrespective of the load level, which can be related to the specific function during the standing position. on the other hand, IC and MU presented higher MFreq intercepts compared to LT, demonstrating possible differences in the muscle fiber conduction velocity of these muscles. These findings suggest that trunk muscles are differently activate during upper limb exercises, and the fatigue process affects the lumbar muscles similarly. (C) 2008 Elsevier Ltd. All rights reserved.

Análise fotogramétrica e subjetiva do perfil facial de indivíduos com oclusão normal

OBJETIVO: avaliar o perfil facial em fotografias de jovens brasileiros leucodermas com oclusão normal. METODOLOGIA: 58 fotografias de perfil de 23 jovens do gênero masculino e 35 do feminino, com idade média de 16,03 ± 2,04 anos, que apresentavam 4 das 6 chaves de oclusão de Andrews. As fotografias foram julgadas por 21 alunos e 2 professores de pós-graduação. Também foi feita fotogrametria dos integrantes da amostra. RESULTADOS E CONCLUSÕES: verificou-se que a oclusão normal natural não foi indicativa de beleza do perfil facial, visto que 28% dos perfis avaliados foram classificados como desagradáveis. Dentre as medidas pesquisadas para os grupos de perfis agradáveis, aceitáveis e desagradáveis, verificou-se que poucas foram as que se apresentaram estatisticamente diferentes, chamando a atenção para o fato que, isoladamente, as medidas fotogramétricas do perfil facial não poderiam indicar beleza do perfil.

A influência da redução do espaço nasofaringeano na morfologia facial de pré-adolescentes

A redução do espaço nasofaringeano devido à hipertrofia adenoideana leva a adaptações posturais da cabeça, mandíbula, língua e lábios, podendo causar alterações no padrão esquelético facial. Foram coletadas 98 teleradiografias em norma lateral de pré-adolescentes na faixa etária de 7 a 10 anos na Clínica de Ortodontia da F.O. Araraquara, as quais foram selecionadas levando-se em consideração a dimensão da imagem do espaço nasofaringeano (ENF) (correspondente à menor distância do dorso do palato mole à parede faringeana posterior). As radiografias foram divididas em 3 grupos: Grupo I (estreito), ENF entre 1,7 e 5,1mm; Grupo II (médio), ENF entre 5,2 e 7,6mm; Grupo III (amplo), ENF entre 7,7 e 12,9mm. Utilizamos duas medidas angulares e seis medidas lineares para caracterizar a morfologia facial. As médias e o desvio padrão de cada medida efetuada foram obtidas, e por meio de teste de análise de variância (ANOVA), verificou-se diferença não significativa entre os grupos para as variáveis: ANperp, p=0,07; PgNperp, p=0,058, comprimento mandibular, p=0,15, comprimento maxilar, p=0,06, diferença maxilomandibular, p=0,98, eixo facial, p=0,96, altura facial inferior, p=0,84 e significativa na variável plano mandibular (p<0,01). Portanto, a redução do espaço nasofaringeano está associada a alterações no plano mandibular, que apresentou valores maiores com a diminuição do espaço nasofaringeano.

Electromyographic study of the temporal, masseter and suprahyoid muscles in the mandibular rest position

The temporal muscles (anterior position), and the masseter and suprahyoid muscles were studied electromyographically in 15 subjects with ages ranging from 18 to 35 years, showing normal occlusion (Class I of angle), complete dentition and no dysfunction of the stomatognathic system. The volunteers sat comfortably in a chair, keeping the Frankfurt plane parallel to the boor; the muscles were analysed in the mandibular resting position through a number of stages: with minimum exteroceptive stimuli, relaxation with soft music, abolition of the intrabuccal negative pressure through a plastic tube, stress provoked by an electronic game, disocclusion of posterior teeth using the occlusal splint and finally withdrawal of this device. The electromyographic results were analysed statistically. The samples, were analysed for all of the frequencies of motor units, in a 1-min period. It was found that there were statistically significant difference between the relaxation stages as compared with the withdrawal of negative intraoral pressure and mainly with the stress phase, being this only on the suprahyoid muscles, with 5% significance.

ANATOMICAL STUDY OF THE OPOSSUM (DIDELPHIS-ALBIVENTRIS) EXTRAOCULAR-MUSCLES

The anatomy of the extraocular muscles was studied in 10 adult opossums (Didelphis albiventris) of both sexes. Eight extraocular muscles were identified: 4 rectus muscles, 2 oblique muscles, the levator palpebrae superioris and the retractor ocular bulbi. The rectus muscles originate very close one to another between the orbital surfaces of the presphenoid and palatine bones. These muscles diverge on the way to their insertion which occurs at about 2 mm from the limbus. The levator palpebrae superioris originates with the dorsal rectus and is positioned dorsally in relation to it. The retractor ocular bulbi forms a cone which embraces the optic nerve and is located internally in relation to the rectus muscles. The dorsal oblique originates on the presphenoid bone and after a tendinous trajectory through a trochlea on the medial wall of the orbit, inserts into the ocular bulb. The only muscle arising from the anterior orbital floor is the ventral oblique. The main nerve supply for these muscles is the oculomotor, except for the dorsal oblique which is innervated by the trochlear nerve, and the lateral rectus which is innervated by the abducens nerve. The retractor ocular bulbi receives branches from the inferior division of the oculomotor nerve and some branches from the abducens nerve.

Clinical evaluation of tinnitus in patients with sleep bruxism: prevalence and characteristics

Evaluation of the prevalence and characteristics of tinnitus in a Brazilian series of sleep bruxism patients. In this descriptive study, 100 patients (80 women and 20 men) were selected through the self-report of grinding teeth during sleep, confirmed by room mate or family member. They were evaluated according to a systematized approach: a questionnaire for orofacial pain and the Portuguese version of the Research Diagnostic Criteria for Temporomandibular Disorders. The patients were divided into two groups: group A, 54 patients with complaint of tinnitus and group B, 46 patients without tinnitus complaint. The mean age was 37.85 (13-66 years) and 34.02 years (20-59 years), respectively, for groups A and B (P = 0.1164). There was statistically significant difference between the two groups, with higher prevalence for the group A, in relation to: presence of chronic facial pain (P = 0.0007); number of areas painful to palpation in the masticatory and cervical muscles (P = 0.0032); myofascial pain in the masticatory muscles (P = 0.0003); absence of teeth without prosthetic replacement (P = 0.0145) and indices of depression (P = 0.0234). Structural alterations of the TMJ, like disc displacement and vertical dimension loss did not differ for the two groups. Tinnitus frequency was higher in patients with sleep bruxism and chronic facial pain. Myofascial pain, number of areas painful to palpation in the masticatory and cervical muscles, higher levels of depression and tooth absence without prosthetic replacement were more frequent in the group with tinnitus.

Experimental study of progressive facial hemiatrophy: effects of cervical sympathectomy in animals

Progressive facial hemiatrophy (Romberg's syndrome) is of unknown cause and uncertain pathogenesis. The main pathogenetic hypotheses are: sympathetic system alterations, localized scleroderma, trigeminal changes, possibly of genetic origin. To test the hypothesis of sympathetic system alterations, we designed an experimental model with ablation of the superior cervical sympathetic ganglion in rabbits, cats and dogs. All the animals were operated upon when 30 days old and were examined monthly for 1 year. During this period localized alopecia, corneal ulceration, keratitis, strabismus, enophthalmos, ocular atrophy, hemifacial atrophy and slight bone atrophy on the side of the sympathectomy were observed. Thus, cervical sympathectomy reproduces in animals the principal clinical alterations of Romberg's syndrome. Our data suggest that the sympathetic system is involved in the pathogenesis of this syndrome.